The scientists used this number to make a wider estimate that the new population may contain up to two thousand Borneanorangutans.

With roughly 50,000 orangutans thought to remain in the wild, the new find could add 5 percent to the world’s known orangutan numbers, said Erik Meijaard, senior ecologist for the Nature Conservancy in Indonesia.

Ape Haven

The International Union for Conservation of Nature lists the Bornean orangutan as endangered, pegging the species’ decline to habitat loss due to agriculture and logging.

But this newfound group faces few threats from humans, because the region’s rocky landscape cannot be easily developed into plantations, Meijaard said.

“We almost invariably talk about declining populations. … This is one of the new kind of positives [out] there.”

The unusual ecosystem initially led Meijaard and other conservationists—who have been surveying the region since the early 1990s—to believe that orangutans didn’t exist there in large numbers.

That’s because the animals usually prefer swampy, diverse forests with lots of fruit trees.

But in addition to the ape nests, the expedition team found several varieties of fruit trees growing on limestone plateaus in the region.

A Real Chance

With the forests’ lack of development potential, “there’s a clear local interest in keeping the area the way it is,” Meijaard said.

The Indonesian government is considering making the newfound apes’ home a protected area, he added.

“It is good to hear that there are more orangutans out there and that these new populations are basically protected because of their remoteness,” Melvin Gumal, director of the Malaysia program for the Wildlife Conservation Society, commented via email. Malaysia rules about a third of Borneo.

“However, we also need to protect the existing populations in Borneo and [the Indonesian island of] Sumatra, not just from poaching but from the large-scale changes to their habitats, e.g. commercial agriculture,” Gumal said.

“For orangutans, we have a real chance to protect and save this species—and we need make it happen now.”